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Marine and Tropical Science Research Facility (MTSRF) - Project 3.7.2: Connectivity and Risk: Tracing materials from the upper catchment to the reef

Project manager: Jon Brodie & Stephen Lewis

Project staff: Zoe Bainbridge, Leo Lymburner

Collaborators: Katharina Fabricius (AIMS), Craig Humphrey (AIMS), Barry Bennett (AIMS), Cary mcLean (AIMS), Malcolm McCulloch (ANU), Jacky Croke (ADFA), Perran Cook (CSIRO)

Funding: MTSRF & GBRMPA

Timeline: Mid 2006 – late 2008

Summary:

Key objectives:

  • Tracing of materials in the terrestrial environment: generation, transport, transformation, trapping

  • Tracing of materials in the marine environment: transport, transformation, trapping, fate

  • Inshore-offshore sediment transport in the Wet Tropics: relationships between sediment input and transport, and regional turbidity regimes

  • Floodplain sedimentation dynamics in Dry Tropics catchments: the role of riparian and floodplain vegetation

The principal objectives of this project are to assess the risk to GBR ecosystems from the various land-sourced pollutants entering the GBR. Risk will be assessed by establishing explicit links between the sources of pollutants within catchments (land uses, land management practices), delivery of these materials in the GBR lagoon (incl. trapping, transformation and storage regimes). Thus exposure of GBR ecosystems (particularly coral reefs, seagrass meadows, mangrove forests and the water column ecosystem) to land-sourced pollutants can be determined and, in combination with the known toxicities/effect concentrations of the pollutants, risk can be assessed.


The project will characterize and obtain a distinct “fingerprint” of the fine sediments (mud fraction) entering the marine environment, using their isotopic and elemental properties, and link these to the sediment sources of the major terrestrial catchments. It will also examine historical changes in the delivery of terrestrial materials from the major river systems in the Rockhampton-Cairns region into the marine environment using coral and sediment cores. This will involve determining transport mechanisms, residences time and fate of terrigenous materials in the floodplains, estuaries, inshore reefal areas and mid-shelf regions of the Great Barrier Reef, and develop and apply new technologies to specifically trace pathways of the key nutrient elements phosphorus and nitrogen from the terrestrial catchments, through estuaries, inshore coastal zones to the mid-shelf of the Great Barrier Reef.